Castle Peak Police Station (2nd generation) / Marine Police admin facility [c.1955-c.1992]
This replaced the earlier Police Station that was further north near San Hui (see https://gwulo.com/node/45963).
Over at the FB group "The Royal Hong Kong Police Force", Trevor Hollingsbee adds that it was "used it as an admin facility for Marine West Division in the 1990s after it had shut as a police station."
It was replaced by the current Castle Peak Police Station, built on reclaimed land on the west side of Tuen Mun (see: https://gwulo.com/node/45965).
The dates are guesses. We've seen photos of this building from the mid-1950s, and the building that replaced it, Harvest Garden, was completed in 1994 (from "Names of Buildings").